Should we recycle urine on Earth, too?

After five days of tinkering, astronauts aboard the International Space Station ran their first successful test Tuesday of equipment that turns urine into drinking water.

Delivered to the station by the Space Shuttle Endeavour, the $154 million water recycling system, which also processes sweat and moisture from the air, is designed to quench astronauts' thirst while requiring fewer costly resupply missions. Samples of the recycled water will be tested back on earth before astronauts aboard the station can start drinking from the system's tap.

This raises a question: Can we build these things on earth? Maybe even for a little less than $154 million?

A thirsty planet

There's definitely a need. According to the World Health Organization, some 1.1 billion people lack access to clean water. That's almost 1 in 6 human beings. And according to the United Nations Development Programme, women and girls in developing countries collectively spend more than 10 million "person-years" hauling water from remote sources each year.

And it's only getting worse. As a study published in Nature in April predicts that, by 2025 more than half of the world's countries will face freshwater stress or shortages, and by 2050, as much as 75 percent of the world's population could face freshwater scarcity.

A cheap and reliable urine-to-potable-water device could solve what is arguably the world's No. 1 problem, so to speak.

It wouldn't be the first time that NASA's water-purification technology spins off into the developing world. In 2006, engineers from the space agency helped develop a system for the northern Iraqi village of Kendala, which filters and purifies water from nearby streams, wells, and swamps.

H20 is H20

If you think about it, enjoying a refreshing glass of erstwhile whiz is not as disgusting as it sounds. What is "new" water anyway? As NASA astronaut Sandra H. Magnus told the New York Times after pointing out that water flushed down our toilets eventually evaporates and rains down into our reservoirs. "We drink recycled water every day — on a little bit longer time scale."

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